From an ESPN report dated October 2023
"United are working with Onana to help him better deal with errors when they come as well as on the technical side of his game, including stabilising his feet more quickly to help with shots aimed low and around his body. It doesn't help that he has a tendency to get stuck on his goal line when opponents are attacking, and coaches have reminded him to take up more aggressive positions to make the target smaller.
He's been brought to United. primarily, because of his ability with the ball at his feet with UEFA's technical report on the Champions League final against Manchester City noting he "displayed the passing range of a deep midfielder." After eight Premier League games last season, according to ESPN Stats and Information Group, De Gea had completed 134 of his 218 passes (61.47), while Onana has reached 205 from 271 attempts (75.65%), a sign that the Cameroon international is trying to help Ten Hag's side play in a different way."
From ManUtd .com July 2023 EtH on signing Onana
"Most important, always for a keeper, is clean sheets and he's not doing that on his own," began the manager. "Therefore, you need a very good defensive organisation, [it's] quite clear. But also the capabilities of a keeper is [about] keeping the goal clean. So this is the first criterion of a good goalkeeper.
"But, nowadays, football also demands good playing from the back, out-playing qualities, and that is a quality Andre has. You need both and you need to cover both areas. So yeah, we're happy, of course.
"I think with his physical presence and also with his personality, he is so keen on winning. He's so, so eager to win trophies and he will help the team and he will help the squad to get to higher levels."
It's probably quotes like this that lead people to think he would "transform our attack" you will obviously rubbish this even though one of them comes from EtH himself.
Virtually every other report you find about the transfer mentions his ball playing ability and how he can transform possession into an attack.
But hey you have 131K posts so you are right, and the vast majority of people in this thread are wrong.